Comunity Cases - An Idea Trade for Portable Cases

Hello! -first topic- I've noticed there's plenty of Portable Game Cases for the Pi, but most of them are rather 'expensive' ($80+ USD) which is sadly currently beyond me at the moment. I'll be honest I was aiming for a PiGranate or similar. But above the money there's something that bugs me, there's no "modularity" as in you can't take off the Pi and use it outside the case, some cases solider directly to the pi, (Pi Zero is an exception) which ultimately kills that part. It feels that you're stuck with a game console, and not an optional PC. Some very specific cases cut all connectivity with the pi (no usb, hdmi, etc) so I'm posting here , not to complain (that part's done) but to have an open idea and suggest topic on a much easier, more accessible and hopefully more 'free' (freedom) case ideas and have others build on it! Of course, everyone does things their way, most of the time anyway, but might like to share their mods and some might take suggestions.

That's about $47-$60 compare to some cases. Of course, add the Battery and any extra components, keep in mind, this was made with the Pi3 in mind. However, because I am new at this (another motive for making this topic), of course there are some issues such as;

No Idea how I'm gonna power up the screen, probably through the PowerBoost